Hong Kong, China—Pharmacists should be aware of an increased risk of neuropsychiatric events associated with Helicobacter pylori therapy containing clarithromycin.

That’s according to a study published online by JAMA Internal Medicine, which notes that past research has raised concerns about the possibility of acute neuropsychiatric events with H pylori therapy using the antibiotic marketed as Biaxin.

For the self-controlled case series study, University of Hong Kong researchers used the local Clinical Data Analysis and Reporting System database to seek out associations.

To be included in the research, adult participants must have had both exposure to H pylori therapy containing clarithromycin and their first recorded neuropsychiatric events between January 1, 2003, and December 31, 2012. A post hoc nested case-control analysis was also performed in patients receiving H pylori therapy containing clarithromycin.

Included were 66,559 patients, nearly half male, who had at least one outpatient prescription of H pylori therapy containing clarithromycin. The average age was 55.4 years at first exposure.

The primary outcome was defined as composite neuropsychiatric events, with psychotic events and cognitive impairment considered secondary outcomes. The study authors also defined risk periods: 14-day pre-exposure period; current use (Days 1-14 since prescription start date) and recent use (Days 15-30).

Results indicate that 1,824 patients had their first recorded composite neuropsychiatric events during the study period. The study reports an increased incidence rate ratio (IRR) of 4.12 during current use but not in recent use, which had an IRR of 0.95.

“Similarly, both the risk of psychotic events and cognitive impairment increased during current use vs baseline, although this subsequently returned to baseline incidence levels during recent use,” study authors point out.

They found that the crude absolute risks of composite neuropsychiatric events, psychotic events, and cognitive impairment during current use were 0.45, 0.12, and 0.12 per 1,000 prescriptions, respectively, with a nested case-control analysis providing similar results to that of the self-controlled case series analysis.